Sealing film dressing

ABSTRACT

Provided is a film dressing that includes a thin plastic film coated with an adhesive, and a carrier layer applied on the plastic film on a side opposite to the adhesive coating. The adhesive coating has a softness of 10-22 mm and a weight per unit area of 50 g/m 2  or more.

TECHNICAL FIELD

The present invention relates to a film dressing comprising a thinplastic film coated with an adhesive.

BACKGROUND ART

At the start of the 1980s, a new type of wound dressing was launched bySmith&Nephew, a company which manufactures wound dressing products. Theproduct, which is still on the market and is sold under the nameOpSite™, is based on an invention that is described in British patent GB1280631. The dressing consists of a very thin polyurethane film, ca 25micrometres, that is coated with a thin, self-adhesive layer ofadhesive, also ca 25 micrometres. Due to its thinness, the film is veryflexible and pliant. It can be attached securely and can seal relativelytightly around wounds on non-smooth skin surfaces, both convex andconcave. Any wrinkles that are formed, however, sometimes produce thinchannels, through which fluid is able to leak. This dressing, which wastotally unlike all previous dressing products, formed an entirely newcategory known as self-adhesive film dressings. More companies followedwith similar products, and today large numbers of film products with asimilar function and characteristics are available on the market. Thesefilm dressings soon found an important application for the securing andprotection of intravenous cannulas (for example of the Venflon cannulatype). They are also used to cover different types of wound, for examplesites from which skin is removed in conjunction with skintransplantation.

A significant factor for the major sales success of the film productswas, apart from the above-mentioned characteristics, the successfuldevelopment of effective application systems. The thin dressings areextremely difficult to handle without specially designed applicationsystems. For this purpose, therefore, a more rigid carrier material isnormally attached in a removable fashion to the non adhesive-coated sideof the film in order to impart rigidity to the product, which wouldotherwise easily become tangled up in conjunction with its applicationto the skin. The carrier material, which imparts rigidity to the thinfilm, is not removed from the product until the self-adhesive film hasbeen applied in the intended place.

The film dressings have been improved in a variety of ways in morerecent times. Specially designed intravenous securing films have beendeveloped with a perforated narrow slot to leave space for the tubeconnection of the intravenous cannula and, in so doing, to improve itsfunction. A number of film dressings have been provided with a wound padwhich covers the central part of the adhesive-coated side (a so-calledisland dressing), so that a certain degree of absorption of fluid fromthe wound is achieved when the film dressing is applied over a wound.

The above-mentioned category of dressing, self-adhesive film dressings,has nevertheless shown itself to have a number of weaknesses:

1. Relatively aggressive adhesives have been used in order to achieve asecure fixing without the risk of the film dressings becoming loose. Themanufacturers selected aggressive types of adhesive in order to satisfythemselves that the dressings are already attached to the skinsufficiently securely immediately after application. The reason for thisis to avoid the intravenous cannula becoming loose inadvertently, whichwould constitute a risk to the safety of the patient. It is also wishedto avoid wound fluid from weeping wounds penetrating the adhesive jointbetween the film and the skin and leaking out onto the healthy skinoutside the dressing. The types of adhesive used today possess thecharacteristic that the adhesion to the skin increases substantiallywith time. The adhesive strength of many film dressings is multipliedseveral times over after a few hours or days, compared with the adhesionimmediately after application. When film dressings are attached toostrongly, they often cause reddening and pain when they are removed fromthe skin. They also damage the barrier function of the skin because theytake with them epithelial cells from the skin. In spite of this, amanufacturer may select these types of adhesive because the mostimportant consideration is for the adhesion to be sufficiently gooddirectly after application.

2. In the course of examining the protection against leakage from filmdressings, the applicants identified an unexpected weakness in theordinary film dressings. Studies under the microscope revealed thatfluids are capable of spreading easily under the film dressings, inspite of the fact that they are apparently securely attached to the skinwith an entirely tight seal. It was found that fluid was capable ofspreading for a number of centimetres under the dressings via thenaturally occurring microscopic folds in normal skin. Because theleakage consists of very small quantities and is not visible if theinward leakage of colourless fluids is examined, this has beendisregarded previously. The phenomenon, known as micro-leakage, wasfirst observed when the fluid was dyed with a strongly coloured pigment.The transport of fluids beneath the film dressings can constitute amajor risk to patients because micro-organisms could be transported fromoutside or from the skin under the dressing and into the wound. Aninfection from a central venous catheter (CVC), which will often havebeen covered with a film dressing, can constitute a risk to thepatient's life. Manufacturers of film dressings often market these as“shower proof”. When taking a shower, the risk of the aforementionedtype of micro-leakage naturally increases considerably.

3. The adhesive on the film dressings that are sold today exhibits highadhesion to hairs. Because these dressings are often applied to hairyskin surfaces, pain and pulling out of hairs often occurs when thedressings are removed.

The object of the present invention is to solve the aforementionedproblems while retaining all the advantages offered by the thin elasticcarrier material, such as their softness and pliability, which is theunique strong feature of the film dressing product type.

DISCLOSURE OF INVENTION

This object is achieved by means of a film dressing comprising a thinplastic film coated with an adhesive, characterized in that the adhesivehas a softness of 10-22 mm, and in that the adhesive coating has aweight per unit area of 50 g/m² or more. Micro leakage is prevented bythe fact that the adhesive coating has a high weight per unit area andthe adhesive has high softness. Soft adhesives also exhibit the rightlevel of adhesion directly after application, and the adhesion increaseseither not at all or only slightly with time. Adhesion to hairs is alsoso low that the hairs remain in place almost without exception.

In a preferred illustrative embodiment, the adhesive consists of asilicon elastomer or, alternatively, a hot-melt adhesive.

The film dressing is also leakproof in accordance with the MHC LeakageTest with a groove depth of 75 micrometres.

The thickness of the plastic film is less than 50 micrometres. Theplastic film preferably has a thickness of 12-25 micrometres and abending rigidity of less than 3 mm, and preferably less than 1.8 mm.

The strength of adhesion to steel of an applied dressing preferably doesnot vary by more than 5% during the period from 1 minute to 48 hours.

BRIEF DESCRIPTION OF DRAWINGS

The invention is described below with reference to the accompanyingFigures, in which:

FIG. 1 illustrates schematically a cross-sectional view through a filmdressing in accordance with a preferred embodiment of the invention;

FIG. 2 illustrates schematically the measurement of the strength ofadhesion to the skin;

FIG. 3 shows a cone used for softness measurement;

FIG. 4 illustrates a method of measurement for measuring softness;

FIGS. 5-11 illustrate the MHC Leakage Test;

FIGS. 12-14 illustrate a method of measuring the bending rigidity of aplastic film;

FIGS. 15-17 illustrate a method for measuring the adhesion to steel;

FIG. 18 shows the result of the MHC Leakage Test, and

FIG. 19 shows the adhesive strength as a function of the time for aplurality of dressings.

MODE(S) FOR CARRYING OUT THE INVENTION

Illustrated in FIG. 1 is a cross-sectional view of a film dressing 1 inaccordance with a preferred embodiment of the invention. The dressingconsists of a thin plastic film layer 2 preferably made of polyurethaneplastic, which is coated with a layer 3 of a soft, skin friendlyadhesive. The thickness of the plastic film preferably lies between 12and 25 micrometres, and is less than 50 micrometres in any case. Theweight per unit area of the adhesive layer is equal to or greater than50 g/m².

The plastic film also has a bending rigidity of less than 3 mm, andpreferably less than 1.8 mm, measured using a method as described below.

A carrier layer 4 is also applied above the film layer 2, that is to sayon the side facing away from the adhesive layer 3, in order tofacilitate application of the film dressing. The function of the carrierlayer is to stiffen up the film dressing comprising an adhesive-coatedthin plastic film, and the carrier layer can consist of, for example, apolyethylene film or a polyethylene-coated paper with the polyethylenelayer facing towards the film, and with a thickness of 50-300micrometres. The adhesive layer 3 is protected in a customary fashion bya protective layer 5,6 of a material with low adhesion to the adhesive,for example a polyethylene-coated paper or a polyethylene film.

The carrier layer 4 is preferably co-extruded together with the film, orthe film may be formed on the carrier layer.

In conjunction with the application of the film dressing 2,3, theprotective layer 5 is first removed, after which the dressing ispositioned on the user's skin. The protective layer 6 is then removed,and that part of the dressing that was attached to the layer 6 ispressed securely onto the skin. Finally, the carrier layer 4 is removed.

The bending rigidity of the plastic film is determined by the methoddescribed below. As shown in FIGS. 12 and 13, in a view respectivelyfrom the front and from the side, a test test piece FS, havingdimensions of 15×120 mm, is hung over the edge of a 0.3 mm thick metalsheet. The ends of the test piece FS are reinforced with pieces R oftwo-sided adhesive tape and copying paper having dimensions of 15×40 mm(weight=0.13 g); see FIG. 14. It is important for the sample to be hungover the metal sheet in such a way that the sample hangs down by thesame amount on both sides of the metal sheet. After 30 seconds, apicture of the sample hanging as shown in FIG. 12 is taken with adigital camera. A calibrated ruler is appropriately positioned so thatit is included in the photograph. The bending rigidity is thendetermined from the photograph that has been taken by measuring thedistance between the ends of the sample at a point 5 mm below thetopmost part of the sample. The greater the distance between the ends ofthe sample, the higher is the bending rigidity exhibited by the sampleFS. In order for the plastic film together with the soft adhesive to becapable of following all unevennesses in the skin, the bending rigidityof the film must be less than 3 mm, and must preferably be less than 1.8mm.

A principal function of the adhesive coating 3 is to attach the filmdressing 1 tightly to the skin of the patient, so that the fluid-bornetransport of bacteria between the skin and the adhesive coating isprevented, and to attach the film dressing securely to the skin, so thatthe product remains in place during all the normal loadings to whichfilm dressings are subjected.

The adhesive in the coating must also be skin friendly and must permitremoval of the film dressings without causing damage to the skin. Thisrequirement presents a major problem in the case of those types ofpressure-sensitive adhesive that are currently used as adhesive coatingsfor film dressings. Such adhesives often attach themselves to the skinso strongly that parts of the Stratum Corneum, that is to say theuppermost layer of the skin, become stuck to the adhesive and are pulledaway from the skin when the attachment of the film dressing is released.This can lead to irritation of and damage to the skin, especially forpatients with a sensitive skin, for example patients aged over 70 years,children aged under 3 years, and patients with certain illnesses, suchas eczema, or who are undergoing certain treatments, such as cortisonetreatment.

The silicon elastomer is very soft and possesses low surface energy, andit adapts very well to the skin, that is to say it flows out into anyunevennesses in the skin and creates a large contact surface between theskin and the silicon elastomer. This large contact surface helps thesilicon elastomer to become attached securely to the skin, in spite ofthe fact that the strength of the adhesive attachment of the siliconelastomer to the skin is not in itself so strong. The adhesive strengthconstitutes a measure of the energy required in order to separate/pulloff the adhesive layer from the skin. A contributory factor to the factthat high energy, and thus a high pulling force, are required in orderto remove the silicon elastomer from the skin, in spite of therelatively weak strength of the adhesive attachment, is that a lot ofenergy is consumed in stretching the soft silicon elastomer before itreleases from the skin. The softer and thicker the layer of siliconelastomer, the greater the force/energy required to remove the elastomerfrom the skin.

The use of a harder adhesive will require a stronger strength ofadhesive attachment in order for the pulling force to be as high as fora softer adhesive. A strong adhesive attachment between the skin and theadhesive can easily lead to skin cells being pulled from the skin inconjunction with the removal of the adhesive.

Another disadvantage associated with harder adhesives is that these arecapable of flowing outwards eventually and thus increasing the size ofthe contact surface with the skin, with the result that the pullingforce eventually increases, which can lead to such adhesives eventuallybecoming difficult to remove from the skin. Unlike harder adhesives,softer adhesives such as silicon elastomers achieve their full adhesivestrength all at once so that their pulling force remains constant astime passes.

Because the characteristics of the skin vary from person to person, theadhesive capacity of the adhesive coating to the skin naturally alsovaries for different patients. The adhesive strength is also dependenton the thickness of the soft adhesive and the mechanical characteristicsof the barrier layer. The standard methods for the measurement ofadhesion that are available today use plates of various kinds, forexample made of steel or glass, and they do not produce values that arerelevant for the measurement of the adhesion to the skin. The values forthe strength of the adhesive attachment of an adhesive to the skin, asindicated below, must be measured by means of a method of the kindillustrated schematically in FIG. 2 and developed by the applicants.

Strips of a self-adhesive film dressing, for which the strength of theadhesive attachment to the skin is to be measured, are punched out withdimensions of 25×125 mm. It should be noted that all the strips are alsoprovided with a carrier layer on the rear side of the film dressing.(The function of this carrier layer is to stiffen up the strips whenthey are applied to the skin). The strips are then applied to the skinon the back of healthy volunteers. The strips are carefully smoothedinto place with a finger, and the carrier layer on the rear side of thestrips is then removed. Finally, the strips are pressed securely againstthe skin for 3 seconds with the help of a sponge made of foam plastic(42×182 mm, thickness=48 mm) glued securely to a steel sheet (50×200 mm,thickness=1 mm). The applied pressure is estimated at 6 kN/m². Thestrips are left in place on the skin for 2 minutes. The strips are thenpulled off at a rate of 25 mm/sec, and the removal force F1 is measured.The angle of removal, that is to say the obtuse angle that is formedbetween the surface of the skin and the removed part of the strip, mustbe 135°. The strength of the adhesive attachment of the strip to theskin is constituted by the mean value of the force F1.

Adhesives that are suitable for use in film dressings in accordance withthe invention must exhibit a strength of adhesive attachment of at least0.2-3 N/25 mm in accordance with this method. The strength of adhesiveattachment is preferably 1-2.5 N/25 mm.

Adhesives in accordance with the present invention must exhibit asoftness that exceeds 10 mm measured by means of a method based on ASTMD 937 and ASTM D 51580. Certain deviations, as can be appreciated below,have been made. FIGS. 3 and 4 illustrate this modified method ofmeasuring the softness of an adhesive by causing a cone B with a weightof 62.5 g to penetrate down by the effect of gravity into a 30 mm thicktest piece C of the adhesive for which the softness is to be determined.The test piece is obtained by filling a cylindrical glass containerhaving an internal diameter of 60 mm and an internal height of 35-40 mm,with adhesive to a depth of 30 mm. In the case of a silicon elastomer,it is necessary to fill a non-cured silicon prepolymer into thecontainer, and then to cross-link it to an elastomer in the glasscylinder. The cone used is illustrated in FIG. 3 and has the followingdimensions: a=65 mm, b=30 mm, c=15 mm and d=8.5 mm. In the performanceof the method for measurement of the softness, the cone B is firstlowered down into a position I, as illustrated with broken lines in FIG.4, and in which the tip of the cone just touches the surface of the testpiece C. The cone B is then released, so that it is able to penetratedown into the test piece C by the effect of gravity. The number ofmillimetres by which the tip B of the cone has penetrated into the testpiece C after 5 seconds is measured and constitutes the penetrationvalue P, the value of which is greater in proportion to the softness ofthe test piece. The penetration value P represents the softness indexused in the present invention. A PNR 10 penetrometer supplied by Sommer& Runge KG, Germany is used in the performance of the method.

It has also been found that, in the case of soft, skin friendlyadhesives, which form barriers preventing fluid from flowing throughthem, fluid is capable of leaking through these barriers via cracks inthe skin, folds in the skin or other unevennesses in the skin. Thisleakage can give rise to the propagation of bacteria, which in turn canlead to wound infections.

Surprisingly, it has been found that the above-mentioned risk of leakagecan be eliminated, or at least significantly reduced, for a skinfriendly adhesive if the adhesive is sufficiently soft and possesses asufficiently high weight per unit area.

The method described below, known as the MHC Leakage Test, was developedby the applicants for the purpose of determining whether or not a filmdressing is leakproof. Specimens S with a size of 30×30 mm and acircular hole (d=12 mm) at the centre of the samples are punched fromthe dressing to be tested. A coloured test fluid is prepared by mixing0.2% by weight of Patentbl{dot over (a)}tt V (from VWR International,Sweden) and 0.1% by weight of Teepol Gold (from Teepol Products, UK)with de-ionized water. An aluminium test plate T having dimensions of15×50×50 mm and provided with 15 milled grooves is made; see FIG. 5,which shows a plan view of the top side of the plate, and FIG. 6, whichshows a view from the side of the plate. For a more detailed descriptionof the form of the grooves, see FIG. 7, which shows a cross-sectionalview through a part of the plate.

In FIG. 7, the depth of the grooves is 75 micrometres, although othergroove depths can be used if it is wished to test the protection againstleakage at cracks in the skin or folds in the skin with other depths,for example 50 micrometres or 150 micrometres.

A specimen S is then carefully positioned centrally above the grooves ofthe test plate T in such a way that no air bubbles occur between thetest plate and the specimen; see FIG. 8. No pressure may be exerted onthe sample when it is positioned against the plate, so that, in theevent that air bubbles occur, these must not be forced away with thehelp of the fingers, but the sample must be raised and repositioned, orelse scrapped.

A piece of polyurethane foam (L00562-6, 1.6 mm from Rynel, Inc.,Boothbay, Me., USA) having dimensions of 50×50 mm is then placed abovethe sample S and the test plate T. A mangle made of metal (44 mm wide,r=48 mm, weight =995 g) is then rolled over the foam and the specimen ata speed of 5 mm/second; see FIG. 9. The mangle is rolled back and forthonce over the sample.

The piece of foam is removed from the sample S, and 65 μl of the testfluid are placed in the hole on the specimen with the help of a pipette.The test fluid is distributed uniformly in the hole with the help of thetip of the pipette, so that the fluid reaches every point on the edge ofthe sample. A stop watch is started as soon as all the test fluid isuniformly distributed in the hole. After 30 minutes, a picture is takenwith a digital camera of the specimen S and the test fluid T placed onthe test plate together with a calibrated ruler.

The photograph is used to measure the following distances. For all thegrooves that are in contact with the hole on the sample, that is to sayin all the grooves into which fluid may be expected to penetrate, thedistance d from the edge next to the hole to the edge on the end of thesample is measured; see FIG. 10, which indicates this distance d1 forone of the grooves. All these distances d are then added together, andthey constitute the total distance for which it is possible for thesample to leak. After this, the distance e for which the test fluid hasleaked in all the grooves on the plate is measured; see FIG. 11, whichshows the distance e1 for one of the grooves. The combined length of allthe distances e represents the total leakage distance.

Finally, the leakage is obtained by dividing the combined leakagedistance e by the total distance d for which it is possible for thesample to leak. This quotient is then converted into a percentage figureby multiplying it by 100. The evaluation of the sealing is performed asfollows: Result>10% leakage, regarded as leakage. Result≦10% leakage,regarded as sealing.

Note that, between each measurement performed on the test plate, theplate must be cleaned in the following way. The plate is first rinsedwith water, and it is then washed with n-heptane. It is important toensure that no adhesive residues remain in the grooves on the plate, anda soft material of the nonwoven compress type (Mesoft®, Mölnlycke HealthCare) can be dipped in n-heptane and used to rub away adhesive residuesin the grooves on the plate. Finally, the plate must be left to dry inthe air before it can be reused.

Other solvents may be used for adhesives that are not soluble inn-heptane.

The reason why the test piece should be studied for a time afterapplication is that any leakage will take place by means of capillaryaction, which means that it may be difficult to determine whether or notthe test piece is leakproof immediately after application.

The above-mentioned test method with a groove depth of 75 micrometres inthe grooves of the aluminium plate has demonstrated that a test piececomprising a transparent polyethylene film having a thickness of 25+/−5micrometres with an adhesive coating of a skin friendly adhesive havinga weight per unit area of ca 50 g/m² and a softness of ca 20 mm isleakproof in accordance with this test. It has also been found that atest piece with such an adhesive coating is leakproof on the normal,smooth skin of younger and middle-aged persons. It may accordingly benecessary, in areas of wrinkled skin, to use weights per unit areagreater than 50 g/m² in order to ensure resistance to leakage.

The effect of the resistance to leakage on the softness and the weightper unit area of the adhesive in the adhesive coating has beeninvestigated by the above method in respect of a silicon elastomer,Silgel 612, supplied by Wacker Chemie GmbH, Germany.

In accordance with the MHC Leakage Test with a groove depth of 75micrometres, the leakage was measured for a number of different filmdressings with different softness values and weights per unit area forthe adhesive. All the dressings were manufactured by coating apolyurethane film with a thickness of 25±5 micrometres with Silgel 612with different softness values and weights per unit area. The result isshown in FIG. 18.

The results clearly indicate the existence of a link between thesoftness (penetration) and the weight per unit area of the siliconelastomer. The softer the silicon elastomer, the smaller the weight perunit area required for sealing. The results point to the fact that, fora sufficient number of measurements, it is possible to produce a curvethat indicates exactly the minimum weight per unit area that is requiredat a given softness to ensure sealing against the skin. The results makeit clear that such a curve has a steep incline initially, that is to sayin the case of less soft adhesives, after which it levels out.Accordingly, the relationship between the weight per unit area and thesoftness is such that, in order to achieve sealing at low weights perunit area, very soft adhesives are required, whereas less soft adhesivesrequire higher weights per unit area in order to achieve sealing. It isobvious that it is difficult, and perhaps even impossible, to achievefluid-tight film dressings at softness values below 10 mm. At softnessvalues in the order of 20 mm, a weight per unit area of 50 g/m² may besufficient to achieve sealing.

It should be added that all the known film dressings that were testedwere found to leak.

As can be appreciated from FIG. 18, certain points coincide because anumber of the tested film dressings had approximately the same weightsper unit area and softness values.

Apart from increasing the resistance to leakage, a higher weight perunit area for the adhesive coating is associated with a reduced risk ofblisters, pimples or other damage occurring on the skin at the edges ofthe applied adhesive. Such damage can arise in conjunction withmovements in the film dressing carrier, which lead to relative movementbetween the skin and the adhesive coating, or as a consequence of thedressing being subjected to external loadings, for example in the eventof the film dressing carrier knocking against an object. It has beenfound that the risk of such damage occurring is reduced with a higherweight per unit area and a higher softness for the adhesive coating.This is presumably attributable to the fact that a proportion of theloading is absorbed by the adhesive layer through deformation and is nottransmitted to the skin in this way. The film dressing in accordancewith the invention is also capable of stretching together with the skin,which reduces the risk of shearing occurring between the skin and theadhesive that can give rise to mechanical damage to the skin.

In order to ensure that only a low application force is required inconjunction with the application of film dressings in accordance withthe present invention, it is recommended that the softness of the soft,skin friendly adhesive that is used should be greater than 10 mm, andthat it should preferably lie between 12 and 17 mm. The softer anadhesive, the more rapidly it will flow into any unevennesses in thesubstrate, which means that the film dressings in accordance with thepresent invention are leakproof immediately after their application tonormal skin. At a softness value greater than 17 mm, there is a risk ofthe inner cohesion of the adhesive being too low, so that residues ofadhesive are left behind on the skin in conjunction with the removal ofan applied film dressing.

Another important characteristic of a film dressing in accordance withthe invention is that the strength of adhesive attachment of the soft,skin friendly adhesives that are used in these dressings does not changewith time or changes only to a minor degree with time. This has beenverified by measuring the strength of adhesive attachment to the skinfor a number of known film dressings and a film dressing in accordancewith the invention containing silicon elastomer as an adhesive. Theknown film dressings were Tegaderm™ from 3M Health Care, USA; OpSite™IV3000™ and OpSite™ Flexigrid™from Smith & Nephew Medical Limited,England. Measurement was carried out by means of the method describedabove for the measurement of the strength of adhesive attachment to theskin, with the difference that the measurements were performed after 1minute, 10 minutes and 3 hours. The results are shown in FIG. 19. As canbe appreciated from this Figure, the strength of adhesive attachmentincreased steeply with time for the known film dressings, whereas thedressing in accordance with the invention exhibited in principleunchanged adhesion. In numerical terms, the strength of adhesiveattachment from 1 minute to 3 hours increased by 295% for OpSite™Flexigrid™, 209% for Tegaderm™ and 318% for OpSite™ IV3000™.

The strength of adhesive attachment to steel for the correspondingdressings and the Mefilm® dressing from Mölnlycke Health Care AB, Swedenwas also measured by means of the method described below.

Specimens having dimensions of 25×120 mm are punched from the testmaterial. Pieces of paper having dimensions of 25×250 mm are punchedfrom copying paper. A steel plate (in accordance with ASTM A 666-94 A,50×200 mm) is washed with a lint-free absorbent material saturated inn-heptane, and three washes are performed with this solvent. Finally, afinal wash is performed with acetone instead of n-heptane. The steelplate is then left to dry for at least 10 minutes, but for not longerthan 10 h. The piece of paper is attached to the specimen at one endagainst the adhesive, and the piece of paper is stapled in place using astapler. The important consideration is for the paper to be attached tothe specimen so securely that it is not able to slide off in conjunctionwith the application of a load. The overlap between the specimen and thepiece of paper must be 10-15 mm; see FIG. 15 (view from the side). Thespecimen is then placed against the clean steel plate with the adhesivefacing down towards the steel plate. It is important for the specimen tobe laid carefully onto the steel plate in such a way that no pressure isapplied to the specimen. A piece of polyurethane foam (L00562-6, 1.6 mmfrom Rynel, Inc., Boothbay, Me, USA) is then placed above the sample onthe test plate, and the sample is attached to the plate by rolling amangle (45 mm wide, weight=445 g, r=47 mm) back and forth once over thepiece of foam 1 at a speed of 5 mm/second; see FIG. 16 (view from theside). The specimen is tested after 1 minute or 1 hour after rollingwith the mangle.

The test is performed as follows. The steel plate is clamped securely tothe lower clamp of the tensile testing machine (Instron 4301, Instron4464 or equivalent), so that the piece of paper hangs verticallydownwards. The piece of paper is then folded upwards through 180 degreesand is clamped securely to the upper clamp of the tensile testingmachine; see FIG. 17 (view from the side). The tensile testing machineis started, and the mean force required to pull the specimen from thesteel plate is recorded. The tensile testing machine must operate at aspeed of 300 mm/min.

The mean force for the different film dressings was measured after 1minute and 1 hour. The strength of adhesive attachment increased by 22%for Tegaderm™, by 58% for Mefilm®, by 37% for OpSite™ IV3000™ and by 27%for OpSite™ Flexigrid™ after one hour, whereas no increase in thestrength of adhesive attachment was measured for the film dressing inaccordance with the invention.

Furthermore, no hairs are pulled out when removing film dressingsprovided with soft, skin friendly adhesive.

The products proposed in the present invention are normally suppliedpacked in sterile conditions, which means that the adhesives used mustbe capable of being sterilized, as must other components of sucharticles, of course.

The described embodiment of the invention can naturally be modifiedwithin the scope of the invention. Types of carrier layer other than theplastic layer described here can be used, for example carrier layersmade of paper. It is also possible to apply an absorption body to thedressing in order to produce a so-called island dressing. It is alsoconceivable to apply different substances to the adhesive, for exampleZnO, skin care substances or bactericidal substances, which substancesare so arranged as to leak out slowly onto the skin. It is also possibleto supply hydrophilic particles or similar in the adhesive. Moreover,the film may be perforated with one or more holes or may be slotted. Theinvention must accordingly only be restricted by the content of thefollowing Patent Claims.

1-9. (canceled)
 10. A film dressing comprising: a thin plastic filmcoated with an adhesive; and a carrier layer applied on the plastic filmon a side opposite to the adhesive coating, wherein the adhesive coatinghas a softness of 10-22mm and a weight per unit area of 50 g/m² or more,wherein the plastic film has a thickness of less than 50 micrometers,and wherein the adhesive coating exhibits a strength of adhesiveattachment of at least 0.2 N/25 mm.
 11. The film dressing of claim 10,wherein the adhesive coating comprises a silicone elastomer.
 12. Thefilm dressing of claim 10, wherein the adhesive coating comprises ahot-melt adhesive.
 13. The film dressing of claim 10, wherein the filmdressing is leakproof in accordance with the MHC Leakage Test with agroove depth of 75 micrometers.
 14. The film dressing of claim 10,wherein the plastic film has a thickness of 12-25 micrometers.
 15. Thefilm dressing of claim 14, wherein the plastic film has a bendingrigidity of less than 3 mm.
 16. The film dressing of claim 14, whereinthe plastic film has a bending rigidity of less than 1.8 mm.
 17. Thefilm dressing of claim 10, wherein a strength of adhesion to steel of anapplied film dressing does not vary by more than 5% during a period from1 minute to 48 hours.
 18. The film dressing of claim 11, wherein theadhesive coating further comprises ZnO.
 19. The film dressing of claim12, wherein the adhesive coating further comprises ZnO.
 20. The filmdressing of claim 11, wherein the adhesive coating further comprises askin care substance.
 21. The film dressing of claim 12, wherein theadhesive coating further comprises a skin care substance.
 22. The filmdressing of claim 11, wherein the adhesive coating further comprises abactericidal substance.
 23. The film dressing of claim 12, wherein theadhesive coating further comprises a bactericidal substance.